Could I be pregnant?

For a couple days in a row I’ve woken up feeling absolutely miserable and every morning sometime within an hour of waking up I puke, then I feel better for the rest of the day. It’s been 27 days since I last had sex and I don’t know when my next period should be (they’ve always been irregular). We used protection but could I still be pregnant? Would a home test show up now or should I wait a bit longer?